Power converters are used to convert power from direct current (DC) power sources to alternating current (AC) power output for use on local loads or for delivery to a power grid. Such power converters are instrumental in applications such as for providing AC power from DC distributed power sources like photovoltaic (PV) cells. With an increased societal focus on anthropogenic environmental degradation, particularly in relation to green house gas (GHG) and certain other emissions, there has been an increased trend towards distributed renewable power generation. For example, in recent years, there has been a steep increase in the number of homes and businesses that have installed roof top solar cell arrays that generate power to power a home or business and also provide excess power to the power grid. Such distributed power generation sources may require power converters that are efficient, inexpensive, reliable, and have a minimal form factor.
In distributed generation or point of use generation of power, it is sometimes necessary to temporarily not provide power to the power grid from the distributed generation source. For example, such a situation may arise if there is a temporary drop in the voltage of one or more phases of the power grid, a condition that is sometimes referred to as low voltage ride through (LVRT). Another example of when it may be desirable to temporarily not provide power from a distributed generation source to a power grid may be when a phase jump occurs on the power grid. When a condition arises where power from a distributed generation source cannot be supplied to the power grid, it may be necessary to dissipate power from the power source within the power converter.
Conventional power converters may include a dynamic break to dissipate power temporarily from a power source during times when power cannot be delivered to the power grid. Such dynamic breaks may include a solid state switch that can be gated to apply a shunt resistor to dissipate power either at the input of the inverter or at the output of the inverter of the power converter. Therefore, conventional dynamic breaks in power converters may require additional active devices and associated control mechanisms to dissipate power when power cannot be provided to the power grid from the power converter.